Google has said it plans to open up more spots for its Google Glass Explorer program soon, after devices sold out in its one-day-only sale in the US on Tuesday. However the company is receiving criticism for restricting sales to the US.

The company announced plans to open up its program to allow customers to buy a pair of its smart glasses last week, in a move that created the groundswell of consumer competition Google no doubt anticipated.

Google kept customers updated throughout the day on its Google+ page, and announced that one particular model - Cotton (white) had sold out particularly quickly. At the end of the day the company said those that missed out would have another chance soon, although there is still no sign of when customers outside of the US will be able to get a pair.

“Welcome to our new Explorers! All spots in the Explorer Program have been claimed for now," Google wrote on its social networking site.

“If you missed it this time, don’t worry. We’ll be trying new ways to expand the Explorer program in the future."

There is a webpage where wannabe Glass owners can sign up for future opportunities to part with $US1500 for the unfinished devices, but hopefuls have to be a US resident, with a US shipping address and over 18 years old.

Glass is currently available only through its Explorer program, which focused mainly on potential app developers, who have been able to purchase early versions of the internet-connected glasses to give Google feedback about how to improve them.

“To discover new places, sometimes we need to leave the map behind. And that’s what Glass Explorers do. They are the first to make, to tinker, to create, to shape, and to share through Glass," the Google Glass website says.

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“We’re expanding little by little, and experimenting with different ways of bringing new Explorers into the program."

Google’s decision to limit its Glass program to developers and customers in the US does not apply to corporate clients, with some airlines and banks already revealing their plans for the device.

However some of those unable to get a pair of Google Glass are beginning to express their anger at the US-centric approach.

Australian fitness software developer Nathan Hague let fly at Google on its Google+ page following the close of Tuesday’s sale.

“We’ve asked multiple times and wanted to pay to be early adopters outside of the US and bring to the fitness industry," Mr Hague wrote.

“The reason you’re failing in the marketplace on wearables - and you are failing badly on PR - is that this continued and sustained US-centric approach, grates. You also have done a piss poor job at educating the masses on how their privacy won’t be violated with the camera. You can bleat all you like on that point and labour it massively, but you know what? Noone believes you.

“Companies like us that try to advocate freely for you, have finally got the arse: Your deafening silence on helping us to help you, finally stuck. So listen; Developers like us? Yeah, we’ll stick to Microsoft, Samsung and Apple thanks - at least the SDK’s (software development kits) and the hardware IS forthcoming for companies that WANT to develop and add value."